This application is based on and claims priority under 35 U.S.C. xc2xa7119 with respect to Japanese Application No. 2001-226608 filed on Jul. 26, 2001, the entire content of which is incorporated herein by reference.
This invention relates to a seating detecting device. More particularly, the present invention pertains to a seating detecting device which detects a physique of a passenger and a shape of an object.
A known device is disclosed in Japanese Patent Laid-Open Publication No.10-211836. As shown in FIG. 5, the known device includes a cushion 52, a pressure sensitive switch 53 which is a flexible sheet contained under a recess 51, and a resilient closure 54 which is in contact with a lower surface of the pressure sensitive switch 53, closing the recess 51. The recess 51 is opening toward a bottom which is located in the opposite side of a seating surface in the cushion 52.
Because the known device is only aimed to detect whether a passenger is seated or not, the pressure sensitive switch 53 does not need a large area in a seating area.
However, in order to operate an air bag appropriately as a passenger protection device, an identification of an object on the seat has been needed. More specifically, a judgment of whether an item on the seat is a passenger or an object, and furthermore, if it is a passenger, an identification of a physique of the passenger is needed. In order to obtain such specific information about what is on the seat, a pressure detecting sensor which has a detection area in almost an entire seating area of a cushion is necessary. Also, the pressure detecting device needs to be disposed in a position which is close to a seating surface to assure a detection accuracy.
In addition, normally a seat for a vehicle is structured to fix a surface sheet in the cushion by fixing a suspension wire of the surface sheet with a wire which is embedded in the cushion with a fixing ring. Therefore, if a pressure detecting sensor is disposed in a position which is close to the seating surface, the pressure detecting sensor interferes with the suspension wire of the surface sheet. As a result, a shape of the pressure detecting sensor needs to be formed to avoid an interference with the suspension wire. However, because the suspension wire has various layout patterns in accordance with designs of seats, various forms of the pressure detecting sensor are needed in accordance with the layout patterns of the suspension wire.
Accordingly, it is an object of the present invention to provide a seating detecting device which has an area covering the entire seating surface to be applicable to various design seats.
According to the first aspect of the invention, a seating detecting device is comprised of a first cushion having an insert wire embedded therein, a second cushion placed on the first cushion, a surface sheet placed on the second cushion, a suspension wire fixed to the surface sheet and arranged between the surface sheet and the second cushion, and a pressure detecting device provided between an upper surface of the first cushion and a lower surface of the second cushion and having a plurality of through-holes for the suspension wire being fixed by the insert wire therethrough thereby to fix the surface sheet to the first and second cushions.
According to the second aspect of the invention, the seating detecting device is further comprised of a fixing member fixing the insert wire and the suspension wire.
According to the third and forth aspect of the invention, the seating detecting device is characterized in that the plurality of through-holes is arranged along a first direction and a second direction, and the first direction crosses the second direction.
According to the fifth and sixth aspects of the invention, the pressure detecting device includes a plurality of pressure detecting elements.
According to the seventh and eighth aspect of the invention, the second cushion includes a plurality of through-holes corresponding to the plurality of through-holes of the pressure detecting device.